Piston ring



July 1952 May 1 Fm's gizit BY Kati) Patented July 1, 1 952 PISTON RING Fred Ernst, Gardcna, Calif., assignor to Guy H. Hall, LBS Angeles, Calif.

. Application May 10, 1946, Serial No. 668,860

9 Claims.

; This invention relates :tomea-ns for sealing between a piston and the wall of the cylinder in which the piston operates; more particularly, it relates to such means comprising one or more piston rings which cooperate in a novel manner.

It is known to provide pistons, such as are employed in internal combustion engines, or the like, with a plurality of sealing rings for the-purpose of preventing escape of the combustible mixture between the cylinder wall and the piston, as well asrto prevent passage of excessive quantities of lubricating oil past the piston into the combustion chamber. However, in general, such rings do not have any specialcoo-peration other than what may be termed a cumulative effect, each of the compression rings serving to prevent blow by and to limit the passage of oil independently of the other rings, while the oil ring operates independentl to return most of the oil from the cylinder wall to the crank case.

It is an object of this invention to provide a plurality of piston ring structures which cooperate in a novel manner to effect these functions.

It is another objeotbo-f this invention to provide an improved compression ring and an improved oil ring, adapted to cooperate with each other in a novel manner.

It is another object of this invention to provide an oil ring structure having an axially movable ring member which is economical to manufacture, easily installed on the piston, and which facilitates the provision of large oil return passages. I

It is still another object of this invention to provide a compression ring arranged to provide an oil-filled channel for the dual purpose of form ing a hydraulic seal between the piston and the cylinder wall, and of cooling the piston and ring.

It is another object of this invention to provide an improved piston which may be equally as well used with conventional rings. 1 This invention possesses many other .advan tages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the drawings accompanying and forming part of the present speoification. The form will now be described in detail, illustrating the general principles of the inscale, taken as indicated numbered lineson Fig. 1;. v I 1 Fig. 4 is a fragmentary sectionon an enlarged scale, taken as indicatedb line 4-4-of Fig. 2;

l and Fig 5 is a view similar to Fig. 1, showing the rings in a difierent operating position.

Referring to the drawing, a fragment of a piston is indicated by the numeral l, and a portion of the cooperating cylinder wall is shown at 2. Near its upper end the piston l is provided with a groove 3 accommodating a conventional com- .pression ring 4; A secondgroove 5 is provided below the groove 3 for accommodatinga com-' pression ring structure 6 of-novel form. This structure, comprises an inner or. sealring 1, and an outer ring 8. The inner ring 1 is a split ring formed of steel, cast iron, or a suitable alloy, and

has concentric inner and outer surfaces, as well as parallel faces. adapted to form a fluid-tight seal with the ring lands-or sides of the groove 5.

' outer surface sealing against the cylinder wall 2.

the-cylinder wall 2, the ring 8 traverses the groove f v5 when the directionoi movement of the piston l reverses at the endof the stroke. A spring eX-, pander 9 may be providedwithin the inner ring l ;,for urging rings I and- 8 radially outwardly into sealing relation, so as to providethe seal between the ring 8 and cylinder 2. I v 1,. 7 Another ring groove l 0 is provided in the piston I below the groove 5 for accommodating an oil control ring I I. This ring I! is a split ring with concentric inner and outer surfaces, andhaving a thickness substantially equalto, but not-less than, one-half the width of the groove; l0, to ensure against overlapping of the end portions of the ring. As berorathe ring I I may be formed of cast iron, steel, or other suitablealloy; and, by its resilient engagement with the cylinder wall 2, is caused to traverse the groove iilwhen the direction of movement of the piston is reversed.

The groove 10' is vented to the interior of the piscalledthe ring belt, and indicated by the numeral by correspondingly I2, has a plurality of vertically extending pockets or recesses I3 separated by ribs or posts It which open to the inside of the piston and span the ring groove Ill. The ring groove III is of such depth as to cut partly through the ribs I4, and thus opens into the recesses I3 between the ribs. The ring II has a width substantially less than the depth of the groove Ill; thus, the groove III is vented into the recesses I3, and thence to the interior of the piston, such venting being controlled in accordance withthe position of the ring II.

An expander I5 is provided for the oil control ring II. This expander is the full width of the groove I and, as shown in Fig. 2, engages the bottom of the groove I I) in-alternate posts I l and, at the intermediate posts, engages the inner surface of the ring II. If desired, the expander I may be bent to form lugs I6 and II for engaging opposit sides of one of the posts I4 to restrain the expander against relative angular motion with the piston I. Furthermore, the rin II may be provided with elongated notches, 0r cut-out portions I8 on its inner surface for accommodating the contacting portions of the expander I5. Due to the fact that the expander I5 extends the full width of the groove I0, the'eiiective venting area is formed by those portions I9 of the recesses I3 within the expander I5, and which, obviously, are present on both sides of the groove. They provide a large venting area, permitting free passage of oil from groove III to the interior of the piston I.

The operation of the rings is as follows: on the down stroke or the piston I, rings 8 and II are urged against the upper side of their respective grooves 5' and I0, as shown in Fig. 1. Oil between the piston I and the cylinder wall 2 is scraped into the groove I0 by the control ring II, entering the interior of the piston through vents I9, and thence returning to the crank case.

A small amount of oil escapes past the ring I I and is trapped below the ring 8 in groove 5, where it assists the sealing action of the ring structure by forming a hydraulic seal between the piston I and the cylinder wall 2. Further, this body of trapped oil absorbs heat.

There is a body of oil between rings 8 and II and the lower side of their respective grooves 5 and I0, collected on the down stroke of the piston, which serves to cushion the movement of the rings to the position shown in Fig. 5 in response to the piston starting its up stroke. The oil from below ring 8 escapes through the space above ring II (Figs. 2 and 5) to the inside of the piston via the venting areas I9. Upon the next down stroke, oil is again collected between the rings 8 and II, and subsequently released. The successive bodies of oil trapped and released from the space below the ring 8 assist in cooling the piston and rings, particularly the ring structure 6.

Movement of rings 8 and II in their respective grooves serves to prevent any material carbon accummulation on the rings and the cooperating groove surfaces. This effect is produced by the pounding action of th rings against the sides of the grooves as the piston movement reverses. The pounding action of ring 8 is somewhat retarded by the friction encountered by ring 8 against the cylinder wall and the ring I, and whichis produced by expander 9. Similarly, the pounding action of ring I I is retarded by the friction encountered by ring II against the cylinder Wall and expander I5. The control of pounding in this manner can be such as to reduce the slap or blow to any desired amount. Accordingly, rings 8 and I I can be made quite heavy without danger of producing serious inertia effects.

The piston structure shown herein is described and claimed in a divisional application, Ser. No.

242,881, filed July 23, 1951.

The inventor claims: 1. In a structure for sealing between a piston and a cooperating cylinder wall: a ring structure adapted to be accommodated in a groove in the piston, including a ring member movable axially of the groove, said ring member having an axial width substantially less than the groove and sealing against the cylinder wall and a seal ring extending completely across the groove for sealing between the inside of said ring member and the groove, said ring member serving to trap a body of oil in said groove between the sealing ring and the cylinder wall upon movement of the piston in one direction; and means for venting said body of oil exteriorly' of the groove upon movement of the piston in the opposite direction.

2. In a piston ring structure accommodated in a ring groove in a piston: an outer ring member sealing against the cylinder wall, said ring member having an axial width substantially less than the groove, and movable axially across the groove in response to reversal of movement of the piston; and means extending completely across the groove for sealing between said ring and the groove.

3. In a piston ring structure adapted for accommodation in a ring groove in a piston: an outer ring member for resiliently sealing against the cylinder wall, said ring member having an axial width substantially less than the groove and movable axially across the groove in response to reversal of movement of the piston; and an inner ring member for resiliently engaging and sealing against the inside surface of the outer member, as well as sealing against the sides of the groove.

4. In an oil control device: a piston having a plurality of angularly spaced inwardly opening recesses disposed in the ring belt of tthe piston; there being a ring groove encircling the piston and in direct communication with said recesses; a ring disposed in said groove having a surface resiliently sealing against the cylinder and of substantially less thickness than the width of said groove, said ring being freely movable axially across the groove upon reversal of the piston movement.

5. In an oil control device: a hollow piston having a plurality of angularly spaced projections on the ring belt, extending inwardly from the inner wall of the piston and thereby forming between the projections, recesses disposed in the ring belt of the piston; there being a ring groove encircling the piston intermediate the ends of said recesses, and of a depth greater than the thickness of said ring belt, whereby the groove opens into the recesses; a ring disposed in said groove having a surface resiliently sealing against the cylinder and of substantially less thickness than the width of said groove, said ring being freely movable axially across the groove upon reversal of the piston movement.

6. In a structure for sealing between a piston and a cooperating cylinder wall: a ring structure adapted to be accommodated in a groove in the piston, including a ring member resiliently sealing against the cylinder wall and having a thickness substantially less than the width of the groove; means extending completely across the groove for sealing between the inside of said ring member and the groove; said ring member being movable axially of the groove in response to movement of the piston in one direction for trapping a body of oil therein between the sealing means and the cylinder wall; means for venting said oil to the interior of the piston upon reverse movement of the piston, said means forming a second groove encircling the piston, there being inwardly opening recesses in the piston intersecting said second groove; and a ring axially movable in said second groove and sealing against the cylinder wall.

7. In a structure for sealing between a piston and a cooperating cylinder wall: a ring structure adapted to be accommodated in a groove in the piston, including a ring member resiliently sealing against the cylinder wall and having a thickness substantially less than the width of the groove; means extending completely across the groove for sealing between the inside of said ring member and the groove; said ring member being movable axially 01" the groove in response to movement of the piston in one direction for trapping a body of oil therein between the sealing means and the cylinder wall; means for venting said oil to the interior of the piston upon reverse movement of the piston, said venting means forming a second groove encircling the piston, there being inwardly opening recesses in the piston intersecting said second groove; and a ring in said last mentioned groove resiliently sealing against the cylinder wall and having a thickness substantially less than the width of said second groove so as to move axially thereof in response to reversal in direction of the piston movement for venting said oil.

8. In a ring structure adapted to be accommodated in a piston groove: an inner ring sealing against the opposite sides of the groove; and an outer ring having a thickness substantially less than the clearance between the opposite sides of the groove and in sealing relation to the concentric annular surfaces of the cylinder wall and the said inner ring.

9. In a ring structure adapted to be accommodated in a piston groove: an inner ring sealing against the opposite sides of the groove; an outer ring having a thickness substantiallyless than the clearance between the opposite sides of the groove and in sealing relation to the concentric annular surfaces of the cylinder wall and the said inner ring; and an expander urging both rings outwardly.

FRED ERNST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 14,969 Norwood Oct. 26, 1920 1,313,905 Mummert Aug. 26, 1919 1,566,532 Gersting Dec. 22, 1925 1,736,530 Graves Nov. 19, 1929 1,822,101 Lewis Sept. 8, 1931 1,856,271 Solenberger May 3, 1932 2,078,519 Wilkening Apr. 27, 1937 2,083,636 Caldwell June 15, 1937 2,147,956 Alexandresen Feb. 21, 1939 2,200,015 Alexandresen May 7, 1940 2,228,495 Williams Jan. 14, 1941 2,244,166 Marien June 3, 1941 2,273,703 Gille Feb. 17, 1942 2,310,311 Phillips Feb. 9, 1943 

